1. Field of Endeavor
The present invention relates to sensors and more particularly to a lipid nanotube or nanowire sensor.
2. State of Technology
United States Patent Application No. 2004/0253741 by Alexander Star and George Gruner for analyte detection in liquids with carbon nanotube field effect transistor devices published Dec. 16, 2004 provides the following state of technology information: “A variety of spectroscopic methods are currently used to detect analytes and monitor chemical reactions in a liquid environment. These detection methods, where electronic signal generation in response to an analyte is mediated by an optical step, are sensitive to changes in electronic configurations of the atoms and molecules involved in such reactions. Electronic detection devices with transistor configurations have also been fabricated and used for direct electronic signal generation in response to an analyte, although such techniques however have not yielded fully satisfactory alternatives to spectroscopic detection. The recent emergence of nano-scale devices offers the opportunity to effect extremely sensitive electronic detection of analytes by monitoring the electronic performance of such devices as they are exposed to a test sample environment. Field-effect transistors (FETs) fabricated using semiconducting single wall carbon nanotubes (nanotube FETs, NTFETs) and their electrical performance characteristics have been studied extensively. The conductance characteristics of carbon nanotubes have been found, for example, to be sensitive to the presence of various gases, such as oxygen and ammonia, and thus nanotubes included in an electrical circuit can operate as sensitive chemical sensors. NTFET devices, as well as nanowire-based devices, are promising candidates for the electronic detection of biological species. The mechanism of the electrical responsiveness of these devices to the presence of analytes occurs through transfer of charge between the analyte and the nanotube conducting channel, as evidenced by experiments involving electron donating (NH3) and electron withdrawing (NO2) molecules in gas phase. Such nanotube-based devices have also been configured in such a way that the gate electrode is provided by a buffer, in this configuration these devices can be used as pH sensors.”
United States Patent Application No. 2005/0051805 by Byong Man Kim, et al for microprocessors with improved power efficiency published Mar. 10, 2005 provides the following state of technology information: “Nanotubes comprise nanometer scale tubular structures, typically made from a sheet of carbon atoms known as a graphene. They may be single wall or multi-wall structures. A single-walled carbon nanotube typically comprises an elongated, single hollow tube that is about 1 nm in diameter and few-hundreds-nm to few-hundreds-μm in length. A multi-walled carbon nanotube consists of a plurality of generally concentric, hollow tubes of different diameters that can range up to a few hundreds of nanometers. One popular method of synthesizing high quality carbon-nanotube structures uses a chemical vapour deposition technique based on a vapour-solid interaction of methane and hydrogen with a catalyst in a heated environment, as described by J. Kong, H. T. Soh, A. Cassell, C. F. Quate, H. Dai, Nature, 395, 878 (1998). A carbon-nanotube structure can act as a semiconductor or a metal, depending on its diameter and how it is rolled up from a sheet of graphene, and has been demonstrated to be harder than the steel and a better conductor than copper. Reference is directed to P. McEuen, M. Fuhrer, H. Park, IEEE Transactions on Nanotechnology, 1, 78 (2002). Various devices have been formed from carbon-nanotube structures. Ballistic conduction in nanotube structures has been reported where nanotubes placed between ferromagnetic contacts were used to demonstrate coherent transport of electron spin, as described by K. Tsukagoshi, B. Alphenaar and H. Ago, Nature, 401, 572 (1999). There have been a number of reports on the use of nanotube structures as the channel material of transistors which performed better than state of the art CMOS or SOI prototypes and reference is directed to S. Tans, A. Verschueren, and C. Dekker, Nature, 393, 49 (1998); R. Martel et al., Appl. Phys. Lett., 73, 2447 (1998); and A. Javey et al., Nature Materials, published online: 17 Nov. 2002; doi:10. 1038/nmat769. Logic functions have also been demonstrated from assembly of nanotube transistors, as described in V. Derycke, Nano Letters, 1, 453 (2001) and A. Bachtold et al., Science, 294, 1317 (2001). A single electron memory was demonstrated in which a nanotube channel of a transistor was used as a single electron sensor and manipulator—see M. Fuhrer et al., Nano Letters, 2, 755 (2002). Also, a nanotube channel of a transistor has been used as an IR source, in which the IR emission was achieved by recombining electrons and holes in the nanotube channel, injected from the source and drain of the transistor, as reported by J. A. Misewich et al., Science 300, 783 (2003). The structures described so far are demonstration devices and not apt to yield consistent device characteristics. Various methods of forming heterojunctions in carbon-nanotube structures have been proposed in an attempt to produce more reliable devices. Heterojunctions formed by adjoining carbon-nanotubes of differently rolled-up layers of closely packed carbon atoms of different diameters have been proposed in U.S. Pat. No. 6,538,262 to V. Crespi et al. Structures utilizing mechanical deformation i.e., by straining or bending are described in U.S. patent application Ser. No. 20020027312 A1, Mar. 7, 2002. Chemical doping of carbon-nanotube structures has been proposed by C. Zhou, Science, 290, 1552 (2000) to B. Yakobson. Also, a method of forming a heterojunction in a nanotube structure by means of a heat induced solid-solid diffusion and chemical reaction is described in U.S. Pat. No. 6,203,864 to Y. Zhang and S. Iijima. However, these junction forming techniques are not particularly suited to forming transistor structures. U.S. patent application Ser. No. 20030044608 A1 by H. Yoshizawa discloses a number of nanotube structures in which an outer graphene sheet is chemically modified to change its conductive characteristics, but the resulting structure does not exhibit a transistor action. It has been proposed to use Y-shaped nanotube structures to form transistors as described in U.S. Pat. No. 6,325,909 to J. Li et al. The transistor action results from heterojunctions formed by structural defects in the vicinity of the confluence of the arms of the Y-shaped nanotube and so the device lacks reproducibility. Also, transistors comprising vertically extending nanotube structures have been proposed in U.S. Pat. No. 6,515,325 to W. Farnworth, and U.S. Pat. No. 6,566,704 to W. Choi et al. However, vertical nanotube structures are known to include a high density of various defects and exhibit poor semiconductor properties, degrading performance of the transistor.”